The subject matter of the present invention relates to a workstation software method and system and program storage device adapted for locating naturally occurring, open fractures in rock formations using compressional (p-wave) 2-D seismic data.
Geophysicists use compressional 2-D seismic data to locate zones of faulting that may play important roles in the trapping of hydrocarbons. The reservoirs in which hydrocarbons have historically been located include clastics (sandstones, etc.) and carbonates (limestones, dolomites, etc. . . . ). Since the location of hydrocarbons has become more difficult, nonstandard reservoirs and trapping mechanisms have become increasingly important as targets of exploration and development. Traditional compressional 2-D seismic interpretations techniques use the time, amplitude and velocity attributes of the seismic data to recognize and map structural and stratigraphic features. Sudden vertical displacements of seismic horizons are often interpreted as faulting. Fractures are structural failures of the rock formation but without vertical or horizontal displacement. These features are not recognizable with traditional seismic interpretation methods. Fractures do, however, influence another seismic attribute, i.e. frequency, by attenuating higher frequencies. Extracting and comparing both the dominant frequency and the frequency spectra from a number of intervals located above and below and containing the formation of interest can recognize this frequency attenuation.